440 



HUTCHINSON'S POPULAR BOTANY 



is pushed by its comrades into the bucket, and then crawls out by the 

 passage, the pollen-mass necessarily first comes into contact with the 

 viscid stigma, and adheres to it, and the flower is fertilized. Now at 

 last we see the full use of every part of the flower of the water-secreting 



horns, of the bucket half full of 

 water, which prevents the bees 

 from flying away, and forces them 

 to fall out through the spout, and 

 rub against the properly placed 

 viscid pollen-masses and the viscid 

 stigma." 



A gardener of long experience 

 in Orchid culture informs us that 

 Stanhopea haselojji, which belongs 

 to an allied genus, is cross-pollin- 

 ated in the same way as Coryanthes, 

 save that the half-drowned bees 

 fall out of the bucket, and strike 

 against the pollinium in falling. 



The subject of insect-pollina- 

 tion is inexhaustible, yet even the 

 slightest sketch would be inadequate 

 that failed to contain some refer- 

 ence to the fertilization of the 

 Yucca-plant. It is nearly forty 

 years since Professor C. V. Riley, 

 of Missouri, first announced the 

 method of pollination of the 

 Yuccas by a little white moth, 

 which he christened Pronuba yuc- 

 casella. Since that time much has 

 been written on the subject, and 

 in 1892 Dr. Riley published a valu- 

 able monograph on Yucca pollina- 

 tion, from which we have gleaned 

 most of the particulars given below. 

 The monograph, which extends to 



A. little-known Orchi.1 with preen dowers, which secrete no 



nectai it has no spur but gives off the odour of musk in 



the evening for the attraction of small beetles. 



Photo by-\ 



FIG. 543. MUSK ORCHIS (Herminium 

 monorchis). 



sixty large octavo pages, and is 

 fully illustrated, is included in the 

 third annual report of the Missouri Botanical Garden. 



The Yuccas are a very interesting genus of plants of the lily family, 

 comprising numerous species and even sub-genera, all characterized by 

 anthers not reaching anywhere near the stigma ; so that fertilization 

 unaided can take place only by the merest accident. These plants, in fact, 



